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LOS
ANGELES—Ethanol, widely touted as a greenhouse
gas-cutting fuel, would have serious health effects if
heavily used in cars, producing more ground level ozone
than gasoline, particularly in the Los Angeles basin,
according to a Stanford University study out Wednesday.
“Ethanol
is being promoted as a clean and renewable fuel that
will reduce global warming and air pollution,” said Mark
Z. Jacobson, associate professor of civil and
environmental engineering and author of the study in the
online edition of Environmental Science and Technology.
“But our results show that a high blend of ethanol poses
an equal or greater risk to public health than gasoline,
which already causes significant health damage.”
Ozone is
a key ingredient in smog and inhaled even at low levels
can harm lungs, aggravate asthma and impair immune
systems. The health effects are the same for ethanol
whether it is made from corn or other plant products,
Jacobson found. The study determined that a 9-percent
increase in ozone-related deaths would occur in greater
Los Angeles and a 4-percent increase nationally by 2020 if a form of
ethanol called E85 was used instead of gasoline. In the
Southeast, by contrast, mortality rates were slightly
lower. The type of fuel used in the study, 85-percent
ethanol to 15-percent gasoline, emits less greenhouse
gas than other types, some researchers say.
“Today,
there is a lot of investment in ethanol,” Jacobson said.
“The question is, if we’re not getting any health
benefits, then why continue to promote ethanol.”
Jacobson
used a computer model to simulate air quality in 2020,
when ethanol-fueled vehicles are expected to be widely
available in the United States. His study is the first
to combine emissions data with a host of other
variables, including climate, population density and
already existing amounts of air pollution, he said.
“The
chemicals that come out of a tailpipe are affected by a
variety of factors, including chemical reactions,
temperatures, sunlight, clouds, wind and precipitation,”
he said. “Overall, health effects depend on exposure to
these airborne chemicals, which varies from region to
region. . . . Since Los Angeles has historically been
the most polluted airshed in the US, the test bed for
nearly all US air pollution regulation and home to about
6 percent of the US population, it is also ideal for a
more detailed study,” he wrote.
President Bush has made the increased use of ethanol and
other alternative fuels a centerpiece of his strategy to
increase reliance on domestic fuels while reducing
greenhouse gas emissions. In his State of the Union
address in January, Bush called for annual national
production of 35 billion gallons of ethanol by 2017, up
from 5 billion gallons in 2006, and nearly five times
the target set by Congress. The president’s deputy press
secretary requested a copy of Jacobson’s study Tuesday
but had no immediate comment.
Kristen
Hellmer, a spokesman for the White House Council on
Environmental Quality, said she had not had a chance to
review the study, but reiterated the administration’s
support for ethanol.
“I think
there are pollutants that contribute to ozone which may
slightly increase as a result of more ethanol use, which
can be managed by tools which we have available under
the Clean Air Act,” Hellmer said.
California Air Resources Board spokesman Gennet Paauwe
said staff researchers are designing their own research
to study potential effects of ethanol on air pollution
and health.
Study
author Jacobson said there are already an estimated
5,000 premature deaths annually tied to ozone exposure,
in spite of Clean Air Act regulations. He said he had
assumed large reductions in emissions by 2020 because of
more stringent air regulations, but that even then,
there were significant health risks.
Brooke
Coleman, director of the Renewable Energy Action Project
in San Francisco, described Jacobsen as a respected
air-quality expert, but criticized him for saying there
would be increased deaths from E85 and smog. “He is
ignoring the fact that E85 greatly reduces emissions
that are much more harmful to humans than smog, such as
toxics and soot [particulate],” Coleman said in an
e-mail.
Jacobson
replied that “there is no evidence available to indicate
that particulate matter will decrease with the use of
E85. . . . The effect of E85 on increasing mortality is
firmly ground in science based on information available
today, and not misleading. What is misleading is the
claims made to date that ethanol will improve air
quality and health.” |
